#Sea Levels?
4 messages in this thread
Chris:
If I may venture a reply – I've just joined the forum, so I hope I'm
not off base here. Anyway, I like your attraction to off-beat ideas. To quote
the late astronomer George Abell, "it's good to have an open mind, but not so
open that your brains fall out."
It is hard to say where all that water would have gone to. Can we
narrow the reasonable choices down to continental and sea ice, and atmospheric
water vapor?
Ice being a little less dense than water, that would necessitate a
pretty tall pile of ice to empty a substantial part of the ocean. In fact, if
most of it were in the form of continental ice that would possibly place the
top of the ice cap in the stratosphere. Hard to get any snowfall in the
stratosphere to build that icecap.
And consider the 540 calories per gram required in the heat of fusion
of water, in changing state from liquid to vapor and visa versa. That's a very
great amount of energy required to have been absorbed and released. Where could
it have come from? And can the atmosphere hold that much water vapor?
I know you said, let's not discuss mechanisms, but these things seem to
mainly fall in the category of evidence, seems to me. What evidence would be
required to falsify the idea that that much water was relocated in the last
100,000 years?
Anyone please comment. My field is astronomy, not geology, so don't be
too hard on me, please!
Dear Jim,
I couldn't agree more! And what about the huge increase in ocean salinity?
That would have killed everything! And the stratosphere would have been a mile
or two lower, so that would make it even worse. Er, well, I *think* it would
have been, sort of, if there were 10 miles or so of ice piled up on the
continents. No, it makes no sense at all, it makes plate tectonics look quite
tame by comparison. And if there is evidence of unbroken human habitation on
the continents throughout the past 100k years, I think that would kill the idea
dead. The problem of the canyons seems less easily resolved, but there could
be a "wet" explanation obviously. To form an opinion, then in strict logic one
must decide whether the deep dredgings and borings give evidence of surface or
shallow water deposits formed in situ at the right time. Any idea of mechanism
would have to wait for that. Of course I think your narrowing down of
locations for all that water seem fair, but it IS strictly wrong to do that.
Nothing whatever is relevant except any conclusive evidence for large areas of
dry land where now there are miles of water. The chances of finding that are,
I believe, effectively nil – the canyons are merely intriguing, they are not
solid evidence. None of which will stop me going through those Glomar
Challenger reports carefully in the hope of finding any clear evidence either
way.
I much prefer it in science if facts are presented clearly without causal
hypotheses, when the only hypotheses are of the eyebrow-raising quality which
seem to characterise the 'explanation' of some awkward results. If somebody
says, "Sure, there ARE these canyons and at least one 'delta', sure they look
as though the Atlantic was once nearly dry, but that's absurd for a dozen
excellent reasons. So the best we can come up with is these turbidity ideas,
which may not look too good but they are the best we have," then that's fine by
me. I think awkward facts should be left sticking up where everyone can see
them. That's not being 'open minded', that's just rationality.
Chris
Chris,
OK, you're right about looking for "awkward" facts. This is how
theories advance and get changed.
It looks as if Occam's razor suggests the underwater mechanisms for
carving ocean basin vallies would get first look. Any dry explanations would
require extraordinary evidence.
I was told in my undergrad oceanography course, a long time ago, that
the Med was a dry basin at one period at least. It was fun to imagine the
waterfall through the Strait of Gibraltar when the basin flooded – though it
might have been a relatively tame event if protracted, I suppose. Can't find
the source.
Thanks for your reply.
Tame, I heard one physicist make that statement that his calculations
indicated, and i am not sure of the distance, but is, if a human would have
been anywhere within a few miles of the falls breakout, that the noise of the
water falling would have been so great along with the shock wave, they would
have been rendered permanetly deaf.